The conventional method of tissue preservation often requires 6-24 hours of fixation for tissue samples in 10% formalin or other fixatives, followed by overnight (18-24 hours) processing. This standard practice in pathology has not changed in the past 50 years. However, this method is time-consuming and often results in antigen masking and nucleic acid degradation. Without sufficient preservation of high quality RNA or proteins in fixed tissues, the potential for applying current molecular technologies to clinical pathologic diagnosis is severely hampered. Development of new fixation methods to better preserve the structure of nucleic acids and proteins in the paraffin tissue remains a primary challenge of modem pathologic research and clinical diagnosis. We have recently discovered that high frequency and intensity ultrasound (US) facilitates tissue preservation with greatly improved efficiency and preservation of macromolecule integrity. Using this technique, we have demonstrated in lung and tonsil tissues that 1) the time of preservation is reduced from 24-48 hours to < 1 hour, 2) tissue morphology remains excellent, and 3) high quality and quantity of proteins, DNA and RNA can be preserved. In this proposal, we plan to develop an ultrasound-mediated tissue preservation (UMTP) system applicable to a wide range of tissues and to optimize the physical and biochemical conditions for tissue preservation. Our specific aims are 1) to develop a general-purpose US system for tissue preservation, 2) to compare the efficiency and quality (DNA, RNA and protein availability) of tissue preservation prepared by the UMTP technique and by the standard methods, and 3) to investigate the physical, biochemical and molecular mechanisms of UMTP. Since this novel technique under development has the potential to fundamentally change the practice of tissue preservation in pathology with greatly improved efficiency and molecular integrity, the success of this project could have immediate and significant impact on clinical diagnosis and economic benefits for the patients.